A haybox cooker — also called a fireless cooker — is an insulated box that finishes cooking food without further fuel. The pot is brought to the boil, then nestled into the hay-packed (or straw-, or modern insulation-filled) box, where retained heat slow-cooks the contents for hours. It is the low-tech ancestor of the thermal cooker and the slow cooker: beans, stews, and porridges emerge tender with minimal attention and a fraction of the fuel. Once promoted for economy and wartime fuel-saving, the haybox suits off-grid living, camping, and development work — NGOs have taught it where firewood is scarce. Food safety needs care: the food must stay above danger-zone temperatures, so only suitable dishes and well-insulated boxes qualify.